"I was out camping on Shabbos..."
A host of halachic sha’alos (queries) may arise when a camping trip extends over Shabbos. Campers should stock up on Shabbos-friendly gear and take all precautions regarding halachah, including—but not exclusively—boneh (building), hotza’ah (carrying in the public domain), techum Shabbos (walking distances outside city limits) and muktzah (moving objects not set aside for Shabbos use).
It should be noted that there are so many possible sticky situations with this set-up, that some halachic authorities advise avoiding camping on Shabbos altogether, and some deem it not in the spirit of Shabbos.
If a camper does find themselves on grounds on erev (before) Shabbos, here are two practical examples of the intricacies involved in setting up camp:
Food prep: On erev Shabbos it is forbidden to do hatmanah (wrapping) of food within a heat source for use on Shabbos, even if the food is fully cooked. Therefore, burying a pot of food in hot coals is prohibited.
If most of the pot is not covered by coals it is not considered hatmanah, but removing even a half-submerged pot may cause the coals to spark or die, thereby violating the melachah (prohibition) of mav’ir or mechabeh (kindling or extinguishing a fire). Only a non-Jew may remove the partially covered pot from the coals.
A pot of food that is set completely above the bed of coals may be moved by the Jewish camper if they are careful not to disturb the fire—though in this situation, it is still preferable that a non-Jew take the food off the coals. Obviously, the best set-up for hot Shabbos food would be placing the pot on a device (like a tripod) that elevates the pot of fully-cooked food above the coals, so it doesn’t touch them at all.
(Note that on Shabbos itself, the laws of hatmanah have other—stricter—parameters, which are beyond the scope of this discussion.)
Using the facilities: In places where there are none, it is permissible for campers to relieve themselves on bare earth. The earth used to cover up afterwards must be set aside for this purpose before Shabbos.